Head up displays (HUDs) are typically deployed in vehicles such as automobile or aircraft to allow the driver or pilot to view information projected by the display without requiring the driver or pilot to divert his view away from the outside environment. The optical relay design for such a HUD typically magnifies the generated image formed by a scanning display, liquid crystal display (LCD), or the like, and places the apparent magnified image at some distance outside the vehicle in which the HUD is utilized, for example around one and a half meters away from the operator outside the vehicle where the vehicle is an automobile. The optical relay typically involves a sufficient amount of optical path length for the magnification optics which may provide a design constraint on the physical size of the HUD to provide sufficient magnification and other optical properties such as eyebox size, field of view, and/or distant apparent image location.
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